JP2017094310A - Separation treatment method of treatment object fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separation treatment method of a treatment object fluid capable of effectively restraining fouling (membrane blocking-up) of a separation membrane, and capable of enhancing separation treatment efficiency of the treatment object fluid.SOLUTION: A separation treatment method of a treatment object fluid uses a separation membrane structure 11 having a porous columnar base material 21, a plurality of cells 32 formed by penetrating in the axial direction through the base material 21 and a separation membrane 22 provided on an inner wall surface 321 of the cells 32. In the respective cells 32 of the separation membrane structure 11, a flow passage 33 for circulating the treatment object fluid A is formed on the inside of the separation membrane 22. A flow passage diameter of the flow passage 33 is 1.5 mm or less. When executing separation treatment of the treatment object fluid A, the treatment object fluid A is circulated in the flow passage 33 of the separation membrane structure 11 under a condition of film surface linear velocity of 6 m/s or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a separation processing method for a fluid to be processed.

  Conventionally, a separation membrane structure used for solid-liquid separation or the like is known (see Patent Document 1). The separation membrane structure includes a porous columnar base material, a plurality of cells formed through the base material in the axial direction, and a separation membrane provided on the inner wall surface of the cell. In each cell of the separation membrane structure, a flow path for flowing a fluid to be processed is formed inside the separation membrane.

Japanese Patent Laid-Open No. 10-109022

  However, when the separation process of the fluid to be treated is performed for a long time using the separation membrane structure, solid matter contained in the fluid to be treated adheres to the surface of the separation membrane, and the fouling (membrane clogging) of the separation membrane occurs. . Conventionally, various measures have been taken in terms of structure, such as reducing the inner diameter of the cell of the separation membrane structure, but it cannot be said that fouling of the separation membrane can be sufficiently suppressed. Moreover, it cannot be said that sufficient examination has been made on the conditions for the separation treatment.

  The present invention has been made in view of such a background, and is capable of effectively suppressing fouling (membrane clogging) of a separation membrane and increasing the separation treatment efficiency of the treatment fluid. I will provide a.

  One aspect of the present invention includes a porous columnar base material, a plurality of cells formed through the base material in the axial direction, and a separation membrane provided on an inner wall surface of the cell. A separation treatment method for a fluid to be treated using a separation membrane structure, wherein a flow path for flowing the treatment fluid is formed inside the separation membrane in each cell of the separation membrane structure, The path diameter is 1.5 mm or less, and when performing the separation treatment of the fluid to be treated, the fluid to be treated is circulated in the flow path of the separation membrane structure under the condition of a membrane surface linear velocity of 6 m / s or more.

  According to the separation process method of the fluid to be treated, the separation treatment of the fluid to be treated is performed by setting the flow path diameter of the separation membrane structure to 1.5 mm or less and the linear velocity of the membrane surface to 6 m / s or more. Therefore, when the fluid to be treated flows through the flow path of the separation membrane structure, the shear stress acting on the inner wall surface (the surface of the separation membrane) of the flow path can be increased, and solid matter is formed on the surface of the separation membrane. Etc. become difficult to adhere, and the force to scrape off the solid matter adhering to the surface of the separation membrane becomes stronger.

  Thereby, the fouling (membrane clogging) of the separation membrane due to the solid matter or the like adhering to the surface of the separation membrane can be effectively suppressed, and the separation processing efficiency of the fluid to be treated can be increased. That is, the above-described effects can be obtained by setting the flow path diameter and the membrane surface linear velocity of the flow path through which the fluid to be processed is in the specific range.

  In the separation treatment method of the fluid to be treated, the flow path diameter of the flow path of the separation membrane structure is 1.5 mm or less. When the flow path diameter of the flow path exceeds 1.5 mm, the shear stress acting on the inner wall surface of the flow path (the surface of the separation membrane) is reduced when the fluid to be treated flows through the flow path. The effect of suppressing fouling of the film cannot be obtained sufficiently.

  On the other hand, if the flow path diameter is too small, the pressure loss increases and the speed (flow velocity) of the fluid to be treated becomes slow, so that the fluid to be treated with a high solid content, the fluid to be treated with high viscosity, etc. are separated. Processing may be difficult. Therefore, the flow path diameter of the flow path may be set in accordance with the properties of the fluid to be processed so that the separation process of the fluid to be processed can be performed satisfactorily. The channel diameter of the channel is preferably 0.3 mm or more.

  Here, the flow path diameter (inner diameter) of the flow path means the diameter when the cross section of the flow path is circular, and the hydraulic diameter when the cross section of the flow path is elliptical or polygonal. . The hydraulic diameter is an equivalent hydraulic diameter, and is a diameter of a circular tube equivalent to a cross section of a certain opening. The equivalent hydraulic diameter is generally expressed by 4S / L (S: opening area), L: opening length (periphery length of opening).

  In addition, the cross-sectional shape of the flow path is not particularly limited, and may be, for example, a circular shape, an elliptical shape, a polygonal shape (triangular shape, quadrangular shape, hexagonal shape, etc.) and the like. In order to increase the effect of suppressing fouling of the separation membrane, the cross-sectional shape of the flow path is preferably a cross-sectional shape that does not have corners where fouling easily occurs, for example, a circular shape.

  Moreover, the number of flow paths is not particularly limited. If the number of flow paths is large, the separation treatment of the fluid to be treated can be performed more efficiently. However, after the separation membrane structure is formed, there is a high possibility that cracks or the like will occur between the flow paths. The number of flow paths may be set in consideration of the difficulty in forming the structure.

  In the separation processing method of the fluid to be treated, when the separation treatment of the fluid to be treated is performed, the fluid to be treated is circulated in the flow path of the separation membrane structure under the condition of a membrane surface linear velocity of 6 m / s or more. When the membrane surface linear velocity of the fluid to be treated is less than 6 m / s, the shear stress acting on the inner wall surface (the surface of the separation membrane) of the passage becomes small when the fluid to be treated flows in the passage. Therefore, the effect of suppressing fouling of the separation membrane cannot be obtained sufficiently.

  On the other hand, if the film surface linear velocity of the fluid to be treated is too high, the separation processing performance (efficiency) of the fluid to be treated may be reduced. Therefore, the film surface linear velocity of the fluid to be processed may be set so that the fluid to be processed can be satisfactorily separated. Here, the membrane surface linear velocity of the fluid to be treated refers to a value obtained by dividing the flow rate of the fluid to be treated with respect to the separation membrane structure by the total cross-sectional area of each flow path.

  In the separation treatment method of the fluid to be treated, when the separation treatment of the fluid to be treated is performed, the lower the pressure acting on the surface (membrane surface) of the separation membrane, the less solid matter or the like adheres to the surface of the separation membrane. Thus, fouling of the separation membrane is less likely to occur. Therefore, for example, the transmembrane pressure difference of the separation membrane is preferably 0.5 MPa or less.

  In the separation method of the fluid to be treated, the separation membrane may be a separation membrane for solid-liquid separation. A separation membrane for solid-liquid separation tends to cause fouling. Therefore, the effect of suppressing fouling of the separation membrane can be exhibited more effectively. Note that the separation membrane for solid-liquid separation is, for example, a separation membrane for separating a fluid to be treated containing solid matter.

  Moreover, the separation membrane may include one or more types of filtration membranes selected from nanofiltration membranes, ultrafiltration membranes, and microfiltration membranes. In this case, the effect of suppressing fouling of the separation membrane can be sufficiently obtained for various types of separation membranes while performing the separation treatment of the fluid to be treated satisfactorily.

  Here, the nanofiltration membrane (NF membrane: Nanofiltration Membrane) is a separation membrane having a pore size (pore diameter) of, for example, 1 to 2 nm. The nanofiltration membrane is used, for example, as a membrane that prevents passage of medium to high molecular weight organic substances, multivalent ions, and the like. Applications of the nanofiltration membrane include, for example, concentration of medium to high molecular weight organic substances, softening of hard water, removal of harmful substances, and the like.

  Moreover, the ultrafiltration membrane (UF membrane: Ultrafiltration Membrane) is a separation membrane having a pore size (pore diameter) of, for example, 0.001 to 0.05 μm. The ultrafiltration membrane is used, for example, as a membrane that prevents passage of organic substances, emulsions, fungi, viruses, proteins, and the like having a molecular weight of several hundreds to several millions. Applications of the ultrafiltration membrane include, for example, protein removal, emulsion removal, and CMP wastewater treatment.

  The microfiltration membrane (MF membrane: Microfiltration Membrane) is a separation membrane having a pore size (pore diameter) of, for example, 0.05 to 10 μm. The microfiltration membrane is used, for example, as a membrane that blocks passage of bacteria, fungi, colloids, particles, and the like. Applications of the microfiltration membrane include, for example, polymer catalyst removal, microbial cell removal, polishing waste liquid treatment, purification treatment in water and sewage purification facilities, and the like.

It is sectional explanatory drawing which shows the structure of a separation membrane structure module. It is a perspective view which shows a separation membrane structure. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is sectional drawing which expands and shows the cell periphery. It is sectional drawing which shows the cross section of the separation membrane structure (base material) of Experimental example 2. FIG. It is sectional drawing which shows the cross section of the separation membrane structure (base material) of Experimental example 3. FIG. It is sectional drawing which shows the cross section of the separation membrane structure (base material) of Experimental example 4.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
As shown in FIG. 1, the separation process method of the fluid to be treated according to the present embodiment includes a porous columnar base material 21, and a plurality of cells 32 formed through the base material 21 in the axial direction. The separation membrane structure 11 including the separation membrane 22 provided on the inner wall surface 321 of the cell 32 is used. Hereinafter, the separation membrane structure 11 and the separation membrane structure module 1 including the same will be described in detail.

  As shown in FIG. 1, the separation membrane structure module 1 includes a separation membrane structure 11 and a housing 12 that houses the separation membrane structure 11 therein. The housing 12 and the structure inside the housing 12 will be described later.

  As shown in FIGS. 1 and 2, the separation membrane structure 11 includes a base material 21, a separation membrane 22, a first seal layer 23, and a second seal layer 24. The base material 21 formed in a columnar shape has a circular first end surface 211 that is one end surface in the axial direction, a circular second end surface 212 that is the other end surface in the axial direction, and an outer peripheral surface 213. In the present embodiment, the base material 21 includes a separation membrane support 31 and an intermediate layer 34 (FIG. 4 to be described later).

  As shown in FIGS. 1 to 4, the separation membrane support 31 is a porous body made of alumina formed in a cylindrical shape having a diameter of 30 mm and a total length of about 1000 mm. The separation membrane support 31 is provided with a plurality of communication holes 311. Each communication hole 311 is formed along the axial direction of the separation membrane support 31 so as to penetrate (communicate with) both end surfaces of the separation membrane support 31 in the axial direction.

  On the inner wall surface 312 of the communication hole 311 of the separation membrane support 31, an intermediate layer 34 serving as a base for the separation membrane 22 is provided. The intermediate layer 34 is made of porous alumina. The average thickness of the intermediate layer 34 is 100 μm. In addition, illustration of the intermediate | middle layer 34 was abbreviate | omitted in FIGS. 1-3.

  A cell 32 is formed inside the intermediate layer 34. That is, the cell 32 is a space formed inside the intermediate layer 34. Each cell 32 is formed along the axial direction of the separation membrane support 31 so as to penetrate (communicate with) both end surfaces (first end surface 211 and second end surface 212) of the base material 21 in the axial direction. 127 cells 32 are arranged concentrically in a cross section orthogonal to the axial direction of the base material 21. The cross-sectional shape of the cell 32 is circular.

  The separation membrane 22 is provided on the inner wall surface 321 of the cell 32 of the base material 21. The separation membrane 22 is an alumina porous membrane having a large number of fine pores having smaller pore diameters than the separation membrane support 31 and the intermediate layer 34. The separation membrane 22 is a microfiltration membrane (MF membrane) having a pore diameter of 0.05 to 10 μm. The separation membrane 22 is a separation membrane for solid-liquid separation for separating the fluid A to be processed containing solid matter into solid matter and other components. The separation membrane 22 separates (filters) the fluid A to be processed flowing in the cell 32 of the base material 21 (specifically, in a flow path 33 described later). 2 and 3, the illustration of the separation membrane 22 is omitted.

  In each cell 32, a flow path 33 through which the fluid A to be processed is circulated is formed inside the separation membrane 22. That is, the flow path 33 is a space formed inside the separation membrane 22 provided on the inner wall surface 321 of each cell 32. The cross-sectional shape of the flow path 33 is circular. The channel diameter B of the channel 33 is 1.5 mm or less. In the present embodiment, the channel diameter B (FIG. 4) of the channel 33 is 1.24 mm. The flow path diameter B of the flow path 33 is expressed by the equation B = C−2 × D, where C is the inner diameter of the cell 32 and D is the thickness of the separation membrane 22.

  As shown in FIGS. 1 and 2, the first seal layer 23 includes the first end surface 211 of the base material 21, the vicinity of the first end surface 211 of the separation membrane 22, and the first end surface 211 of the outer peripheral surface 213 of the base material 21. The neighborhood is covered. The first sealing layer 23 is formed on the outer peripheral surface 213 of the base material 21 and the surface of the separation membrane 22 continuously from the first end surface 211 of the base material 21.

  The second seal layer 24 covers the second end surface 212 of the base material 21, the vicinity of the second end surface 212 of the separation membrane 22, and the vicinity of the second end surface 212 of the outer peripheral surface 213 of the base material 21. The second seal layer 24 is formed on the outer peripheral surface 213 of the base material 21 and the surface of the separation membrane 22 continuously from the second end surface 212 of the base material 21.

  If the material which comprises the 1st seal layer 23 and the 2nd seal layer 24 can prevent the to-be-processed fluid A from leaking through the inside of the base material 21 which is a porous body without passing the separation membrane 22, it will be especially. It is not limited. The first seal layer 23 and the second seal layer 24 penetrate into the pores of the base material 21 and the separation membrane 22, and enhance the adhesion with the base material 21 and the separation membrane 22.

  As shown in FIG. 1, the housing 12 in the separation membrane structure module 1 is a hollow metal container having a space for accommodating the separation membrane structure 11 therein. The casing 12 includes an inlet 131 for introducing the processing fluid A, a discharge port 132 for discharging the concentrate A1 obtained by concentrating the processing fluid A by the separation membrane structure 11, and a processing fluid A including the separation membrane structure. The first recovery port 133 and the second recovery port 134 for recovering the filtrate A2 filtered by the body 11 are provided.

  An O-ring 141 is attached on the first seal layer 23 provided on the outer peripheral surface 213 of the base material 21 in the separation membrane structure 11. An annular metal blocking member 142 is fitted on the first end surface 211 side of the base member 21 through the O-ring 141. An O-ring 151 is attached on the second seal layer 24 provided on the outer peripheral surface 213 of the base material 21. An annular metal blocking member 152 is fitted on the second end face 212 side of the base member 21 through the O-ring 151. The separation membrane structure 11 is housed in the housing 12 via O-rings 143 and 153 between the inner wall surface of the housing 12 and the metal blocking members 142 and 152.

  In the housing 12 in which the separation membrane structure 11 is housed, a first space 161 surrounded by the first end surface 211 of the base material 21 and the inner wall surface of the housing 12, and a second end surface of the base material 21. A second space 162 surrounded by 212 and the inner wall surface of the housing 12 and a third space 163 surrounded by the outer peripheral surface 213 of the base material 21 and the inner wall surface of the housing 12 are formed. The first space 161, the second space 162, and the third space 163 are each kept hermetically sealed.

Next, a method for manufacturing the separation membrane structure 11 will be described.
<Separation membrane support production process>
In this step, the separation membrane support 31 was produced. Specifically, a predetermined amount of alumina powder, methylcellulose, water, lubricant, and the like were mixed and kneaded with a mixer to obtain a clay for extrusion molding. And the precursor of the separation membrane support 31 which has an outer diameter (diameter) 30 mm and the some communication hole 311 was shape | molded using the extrusion molding machine. Then, it dried with the warm air dryer, and the molded object before baking was obtained.

  Next, the molded body before firing was fired in an air atmosphere to obtain a separation membrane support 31. Then, both ends of the baked separation membrane support 31 were excised and polished, and the dimensions of the separation membrane support 31 were adjusted so that the total length was 1000 mm. Thereby, the separation membrane support 31 was obtained.

<Intermediate layer forming step>
In this step, the intermediate layer 34 serving as the base of the separation membrane 22 having separation ability was formed on the inner wall surface 312 of the communication hole 311 of the separation membrane support 31. Specifically, a predetermined amount of alumina powder, a dispersant, water, and the like were put into a mixing pot and pulverized and mixed on a rotating frame. A predetermined amount of an organic binder was added and further mixed to obtain an alumina slurry.

  Next, the separation membrane support 31 was immersed in the alumina slurry, and the alumina slurry was brought into contact with each cell 32 to form a film. At this time, the side surface of the separation membrane support 31 was masked. Thereafter, the separation membrane support 31 was pulled up from the alumina slurry and dried with a hot air dryer. The separation membrane support 31 after drying was fired in an air atmosphere, and the intermediate layer 34 was baked. As a result, the intermediate layer 34 was formed on the inner wall surface 312 of the communication hole 311 of the separation membrane support 31, and the base material 21 having the separation membrane support 31 and the intermediate layer 34 was obtained.

<Separation membrane deposition process>
In this step, the separation film 22 having separation ability was formed on the intermediate layer 34. Specifically, alumina powder, a dispersant, water, and the like were put into a mixing pot, and pulverized and mixed on a rotating frame. A predetermined amount of an organic binder was added and further mixed to obtain an alumina slurry.

  Next, the base material 21 was immersed in the alumina slurry, and the alumina slurry was brought into contact with each cell 32 to form a film. At this time, the side surface of the base material 21 was masked. Then, the base material 21 was pulled up from the alumina slurry and dried with a hot air dryer. The dried base material 21 was baked in an air atmosphere, and the separation membrane 22 was baked. Thereby, the separation membrane 22 was formed on the intermediate layer 34.

<End face sealing process>
In this step, the first seal layer 23 and the second seal layer 24 were formed on both end surfaces (first end surface 211, second end surface 212) of the base material 21 and in the vicinity thereof. Specifically, the outer peripheral portion excluding both end portions of the base material 21 is masked, both end portions of the base material 21 on which the separation membrane 22 is formed are immersed in a glass glaze slurry, and both end surfaces of the base material 21 (first The end surface 211, the second end surface 212) and the vicinity thereof were coated. And it dried with the warm air dryer. Thereafter, the glaze part was baked in an air atmosphere. Thereby, the 1st sealing layer 23 and the 2nd sealing layer 24 were formed in the both end surfaces of the base material 21, and its vicinity.

  1 to 4, the base material 21 (the separation membrane support 31, the plurality of cells 32, the plurality of flow paths 33, the intermediate layer 34), the separation membrane 22, and the first seal layer 23 are obtained. And the separation membrane structure 11 provided with the 2nd seal layer 24 was obtained.

Next, a separation processing method for a fluid to be processed according to this embodiment will be described.
The separation process method of the fluid to be treated according to the present embodiment uses the separation membrane structure 11 shown in FIGS. In each cell 32 of the separation membrane structure 11, a flow path 33 for flowing the fluid A to be processed is formed inside the separation membrane 22, and the flow path diameter of the flow path 33 is 1.5 mm or less. And when performing the separation process of the to-be-processed fluid A, the to-be-processed fluid A is distribute | circulated in the flow path 33 of the separation membrane structure 11 on the conditions whose film surface linear velocity is 6 m / s or more. Hereinafter, the separation processing method for the fluid to be processed will be described in detail.

  First, as shown in FIG. 1, the fluid A to be processed is introduced into the first space 161 of the casing 12 from the inlet 131 of the casing 12 of the separation membrane structure module 1. And the to-be-processed fluid A is distribute | circulated in the flow path 33 of the separation membrane structure 11 on the conditions whose film surface linear velocity is 6 m / s or more, and the to-be-processed fluid A is isolate | separated (filtered) by what is called a cross flow filtration system. . Specifically, the to-be-processed fluid A containing a solid substance is isolate | separated into a solid substance and another component.

  In the fluid A to be processed that flows in the flow path 33 of the separation membrane structure 11, only components that can pass through the separation membrane 22 (other components other than solids) pass through the separation membrane 22. The filtrate A2 that has passed through the separation membrane 22 passes through the inside of the base material 21, flows out from the outer peripheral surface 213 of the base material 21 into the third space 163 of the housing 12, and then the first recovery port 133 and the second recovery port. It is recovered from the mouth 134. On the other hand, the concentrated liquid A <b> 1 concentrated through the separation membrane structure 11 flows out into the second space 162 of the housing 12 and is then discharged from the discharge port 132.

Next, functions and effects of the separation processing method for a fluid to be processed according to this embodiment will be described.
According to the separation treatment method of the fluid to be treated of this embodiment, the flow path diameter B of the separation membrane structure 11 is set to 1.5 mm or less, and the membrane surface linear velocity is set to 6 m / s or more. Perform separation processing. Therefore, when the fluid A to be processed flows through the flow path 33 of the separation membrane structure 11, the shear stress acting on the inner wall surface of the flow path 33, that is, the surface of the separation film 22, can be increased. The force which scrapes off the solid substance adhering to the surface of 22 becomes strong.

  Thereby, the fouling (membrane clogging) of the separation membrane 22 due to the solid matter or the like adhering to the surface of the separation membrane 22 can be effectively suppressed, and the separation processing efficiency of the fluid A to be treated can be increased. That is, the above-described effect can be obtained by setting the flow path diameter B and the membrane surface linear velocity of the flow path 33 through which the fluid A to be treated flows to the specific range.

  In the present embodiment, the separation membrane 22 is a solid-liquid separation membrane. A separation membrane for solid-liquid separation tends to cause fouling. Therefore, the effect of suppressing fouling of the separation membrane 22 can be exhibited more effectively.

  The separation membrane 22 is a microfiltration membrane (MF membrane). Therefore, the effect of suppressing fouling of the separation membrane 22 can be sufficiently obtained while the separation treatment (filtration) of the fluid A to be treated is favorably performed by the separation membrane 22.

  As described above, according to the separation processing method of the fluid to be processed according to the present embodiment, the flow path diameter B and the membrane surface linear velocity of the flow path 33 through which the fluid A to be processed flow are within the specific range, thereby separating the fluid. The fouling (membrane clogging) of the membrane 22 can be effectively suppressed, and the separation processing efficiency of the fluid A can be increased.

(Experimental example)
In this experimental example, the effect of the separation processing method of the fluid to be processed according to the present invention was examined. Specifically, a plurality of separation membrane structures (Experimental Examples 1 to 4) were prepared, and a filtration test using a model solution was performed on each separation membrane structure to evaluate fouling (membrane clogging).

The separation membrane structure of Experimental Example 1 is the separation membrane structure 11 of Embodiment 1 as shown in FIGS. 1 to 4 described above. The number of cells 32 is 127, and the flow path diameter of the flow path 33 is 1. .24 mm.
As shown in FIG. 5, the separation membrane structure of Experimental Example 2 is the separation membrane structure 11 having the same basic configuration as that of the first embodiment, and has 91 cells 32 and a flow path 33. The path diameter is 1.44 mm.

  As shown in FIG. 6, the separation membrane structure of Experimental Example 3 is a separation membrane structure 911 having the same basic configuration as that of the first embodiment described above, the number of cells 32 is 91, and the flow rate of the flow path 33 is The path diameter is 1.84 mm.

  As shown in FIG. 7, the separation membrane structure of Experimental Example 4 is a separation membrane structure 911 having the same basic configuration as that of the first embodiment, and has 37 cells 32 and a flow path 33. The path diameter is 2.84 mm.

<Evaluation of fouling (membrane occlusion)>
A filtration test using a model liquid (processed fluid) was performed on each separation membrane structure. Specifically, the separation membrane structure was attached to the same separation membrane structure module as in the first embodiment, the model liquid was supplied from the supply tank to the separation membrane structure, and filtration was performed by a crossflow filtration method. . Note that the concentrated solution and filtrate that passed through the separation membrane structure (separation membrane) were made into a piping system that returned to the supply tank again, so that the concentration of the model solution supplied from the supply tank was always constant. As a model solution, a solution obtained by dissolving skim milk powder with water was used. Filtration conditions were such that the transmembrane differential pressure of the separation membrane was 0.2 MPa, the membrane surface linear velocity of the model liquid was 4 to 7 m / s, and the liquid temperature of the model liquid was 25 ° C.

  After performing filtration for 2 hours by a cross flow filtration method, the separation membrane structure was washed with pure water. The cleaning conditions were such that the transmembrane differential pressure of the separation membrane was 0 MPa, and the membrane surface speed of pure water was 2 m / s. After washing, the separation membrane structure was taken out from the separation membrane structure module and dried in a hot air dryer at 80 ° C. for 2 hours. After drying, the mass of the separation membrane structure was measured, and the increment was calculated relative to the mass before the filtration test. This increase was regarded as the mass of solid matter contributing to fouling, and the presence or absence of fouling was determined by whether or not there was a mass increase of 0.1% or more. That is, when the mass increase was less than 0.1%, no fouling was indicated (O), and when the mass increase was 0.1% or more, fouling was indicated (X).

  As can be seen from Table 1, in Experimental Examples 1 and 2, since the flow path diameter of the separation membrane structure is 1.5 mm or less, the film surface linear velocity of the model liquid (processed fluid) is 6 m / s or more. It was found that the effect of suppressing fouling (membrane occlusion) can be sufficiently obtained.

  On the other hand, in Experimental Examples 3 and 4, since the flow path diameter of the separation membrane structure exceeds 1.5 mm, even if the film surface linear velocity of the model liquid (processed fluid) is set to 6 m / s or more, the Fau It turned out that the effect which suppresses a ring (film | membrane obstruction | occlusion) is not acquired.

  From the above results, in the separation treatment method for a fluid to be treated according to the present invention, the flow passage diameter of the separation membrane structure is 1.5 mm or less, and the film surface linear velocity of the treatment fluid is 6 m / s or more. Thus, it was found that fouling (membrane occlusion) can be effectively suppressed.

(Other embodiments)
It goes without saying that the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the present invention.

  (1) In the above-described embodiment, the cross-sectional shape of the base material 21 is circular, but the cross-sectional shape of the base material 21 is not limited to this. For example, an elliptical shape, a polygonal shape (triangular shape, square shape) Shape, hexagonal shape, etc.).

  (2) In the above-described embodiment, the porous body made of alumina is used as the base material 21, but the material constituting the base material 21 is not limited to this, and for example, mullite, titania, zirconia, etc. It may be a ceramic or a metal material such as stainless steel or titanium.

  (3) In the above-described embodiment, the cross-sectional shapes of the cell 32 and the flow path 33 are circular. However, the cross-sectional shape of the cell 32 and the flow path 33 is not limited to this, and may be, for example, an elliptical shape or a polygonal shape. It may be a shape (triangular, quadrangular, hexagonal, etc.).

  (4) In the above-described embodiment, the porous membrane made of alumina is used as the separation membrane 22, but the material constituting the separation membrane 22 is not limited to this, and for example, mullite, titania, zirconia, It may be zeolite, palladium, carbon, amorphous silica, MOF (metal organic structure) or the like.

(5) In the above-described embodiment, the separation membrane for solid-liquid separation is used as the separation membrane 22. However, a separation membrane for other uses may be used.
(6) Although the microfiltration membrane (MF membrane) is used as the separation membrane 22 in the above-described embodiment, other filtration membranes such as a nanofiltration membrane (NF) and an ultrafiltration membrane (UF) may be used. .

(7) In the above-described embodiment, the separation membrane 22 is composed of one layer, but may be composed of a plurality of layers. Further, although one intermediate layer 34 is provided, a plurality of layers may be provided.
(8) In the above-described embodiment, the base material 21 is configured by the separation membrane support 31 and the intermediate layer 34, but the base material 21 may be configured by only the separation membrane support 31. That is, the intermediate layer 34 is provided between the separation membrane support 31 and the separation membrane 22, but such an intermediate layer 34 may not be provided. In this case, the communication hole 311 of the separation membrane support 31 is a “cell”, and the inner wall surface 312 of the communication hole 311 is a “cell inner wall surface”.

DESCRIPTION OF SYMBOLS 11 ... Separation membrane structure 21 ... Base material 22 ... Separation membrane 32 ... Cell 321 ... Inner wall surface (inner wall surface of cell)
33 ... Flow path A ... Processed fluid

Claims (3)

A separation membrane structure comprising a porous columnar substrate, a plurality of cells formed through the substrate in the axial direction, and a separation membrane provided on the inner wall surface of the cell is used. A method for separating the fluid to be treated,
In each cell of the separation membrane structure, a flow path for circulating the fluid to be treated is formed inside the separation membrane, and the flow path diameter of the flow path is 1.5 mm or less,
When performing the separation process of the fluid to be treated, the fluid to be treated is circulated in the flow path of the separation membrane structure under a condition of a film surface linear velocity of 6 m / s or more. Separation processing method.   The method for separating a fluid to be treated according to claim 1, wherein the separation membrane is a separation membrane for solid-liquid separation.   The said separation membrane contains the 1 or more types of filtration membrane selected from a nanofiltration membrane, an ultrafiltration membrane, and a microfiltration membrane, The separation processing method of the to-be-processed fluid of Claim 1 or 2 characterized by the above-mentioned.